1. Field of the Invention
The present invention relates to a system for selecting oblique images from a collection of geo-referenced oblique images and viewing them within the context of a virtual, three- or four-dimensional (3D space and time) geographic scene.
2. Description of the Prior Art
There are numerous examples in the prior art of systems and methods to select and view images from a collection of images. The most common technique uses a page of thumbnail image views; clicking on a specific thumbnail allows the user to view the desired image.
With respect to geographically referenced images, such as building interiors, exteriors or outside views, it is generally not the image content that drives the user's selection, but rather the image location. In such cases, user interfaces exist that allow the user to click or zoom in on a specific geographic location, and the appropriate image is selected and displayed. Some systems even display multiple images of different views of the same location or adjacent locations as thumbnails or mosaic images stitched together.
In the prior art, image mosaics are generally accomplished using ortho-images (i.e., image surfaces taken at a 90 degree angle to the camera lens). Interior or exterior panoramic views can be created as an image mosaic. With geo-referenced ortho-images, that is, where the image corners are located at a known latitude/longitude on the earth's surface, large image mosaics can be viewed for entire cities, states, countries, even the entire globe at various resolutions.
A recent addition to the substantial collection of geographic images has been the creation of geo-referenced oblique images, that is, images taken not where the subject is placed at a 90 degree angle to the camera lens. Most oblique images are taken at between 30-60 degree angles. Entire cities and states are beginning to take aerial inventories of their geographic and cultural features in great detail. This information is quite valuable if the large warehouses of oblique imagery can be easily accessed. Oblique images do not lend themselves to being stitched together into a mosaic like ortho-images do. To complicate things, the same location may be imaged at many different angles, not just one like an ortho-image. In the prior art, the best user interface to access these oblique imagery warehouses utilize a combination of map point-and-click and thumbnail selection techniques, or “hunt-and-peck” as some users have described the current state of the art.
Prior art oblique image tools do not disclose a system for automatically selecting oblique geo-referenced images from a large image warehouse and displaying for the user the selected image geo-registered within a 3D or 4D (if the images are also time-referenced) computer-generated virtual scene of the surrounding area. Such a system is necessary to provide a natural and easy interface for the user to effectively and efficiently access and analyze oblique imagery from a large image warehouse.